The need to integrate more components on the same substrate involves the need to reduce the dimensions of the patterns represented on the masks, for the dimensions of the monocrystallin substrate cannot be increased very much, for reasons of crystallography and thermal dissipation outside the scope of the invention.
However, constructing high-resolution masks is no longer possible with visible light, whose wavelength is too great, which causes diffraction phenomena on the edges of the patterns of the masks and so poor definition. This is why it is necessary to use for irradiating masking products higher-definition rays, such as gamma rays, X-rays and far ultraviolet rays or electron beams which enable high-resolution masks to be obtained having then greater accuracy in the fineness of the lines--not exceeding a micron in width.
Adaptation to new radiation involves for the masking products adapting their sensitivity to these radiations.
Furthermore, there exist two types of masking products. The "possitive" resins are degraded by radiation, whereas the "negative" resins are Cross-Linked this means that after exposure, an appropriate solvent dissolves the parts of the positive resins which have been exposed to the radiation but, on the contrary dissolves the parts of the negative resins which have not been exposed to radiation. In fact, positive resins are more widely used for obtaining high resolution for their contrast is generally higher than that of the negative resins.
The invention relates then to positive polymer compositions degradable under the action of photons and electrons as well as the process for manufacturing same.
Positive polymer compositions sensitive to photons and electrons are known, such as methyl polymethacrylate, but their sensitivity to different types of photonic and electronic radiation is variable and depends on the corresponding energy absorbed.
For example, insofar as the action of X-rays are concerned, the positive polymer compositions, forming the subject matter of the invention, are more sensitive in a wider range of wavelengths for their structure comprises a plurality of halogenated atoms which selectively absorb the energy in a plurality of spectral ranges, being thus Mutually complementary.